How to know if a memory address is valid for current process or not ?

[dhayden]

Gross violation of the type system just engenders undefined behaviour; a really bad memory access may be 'good' from the limited perspective that the operating system has.

And what are you going to do if you have no OS to rely on?

No argument here. I think we've pretty well determined that there is no standard way to gracefully exit. I'm just showing another non-standard way that might work.

[JLBorges]

> I think we've pretty well determined that there is no standard way to gracefully exit.

There is also no non-standard way to guarantee a graceful exit.
(Other than making complete debug information available which is examined at run-time.)